3D model (JSmol)
|Molar mass||122.42 g/mol|
|Melting point||750 °C (1,380 °F; 1,020 K) decomposes|
|Solubility||insoluble in acid
slightly soluble in aqua regia
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is ?)(|
Palladium(II) oxide is the inorganic compound of formula PdO. It is the only well characterised oxide of palladium. It is prepared by treating the metal with oxygen. Above about 900 °C, the oxide reverts to palladium metal and oxygen gas. It is not attacked by acids.
The structure of PdO is tetragonal (P42/mmc) a = 3.044, c = 5.328 Å. The Pd atoms are square planar as expected for a d8 metal ion and the oxygen atoms are approximately tetrahedral. The closest Pd–Pd distance is 3.044 Å and is almost within the range which can be considered a bonding distance.
PdO is often obtained as a poorly defined material that is generated for applications as a catalyst. Palladium oxide is prepared by heating palladium sponge metal in oxygen at 350 °C.
- 2 Pd + O2 → 2 PdO
- 2 PdCl2 + 4 KNO3 → 2 PdO + 4 KCl + 4 NO2 + O2 (possible reaction)
or the product of dissolving palladium in aqua regia, followed by the addition of sodium nitrate at 600 °C. A hydrated form of the oxide (which dissolves in acid) can be prepared by precipitation from solution, for example, by hydrolysis of palladium nitrate or reaction of a soluble palladium compound with a strong base. The brown hydrated oxide converts to black anhydrous oxide on heating. Its susceptibility to attack by acids decreases at lower water content.
- Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. pp. 1336–37. ISBN 0-08-022057-6.
- Dwight, P.H. (1990). "Preparation and Properties of the System CuxPd1-xO (0<=x<=0.175)". J. Solid State Chem. 86: 175.
- Donald Starr and R. M. Hixon (1943). "Tetrahydrofuran". Org. Synth.; Coll. Vol., 2, p. 566
- Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1965, NY. Vol. 2. p. 1583.
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